CHO cell lines are derived from the ovary of the Chinese hamster (Cricetulus griseus) Tjio, J. H., and Puck T. T. (1958) J. Exp. Med., 108(2), pp. 259-268). They are considered an ideal system for expressing recombinant proteins as post-translational protein modification is similar to that of human cells. Thus, they are the most widely used mammalian cells for transfection, expression, and large-scale recombinant protein production. CHO cells have a well-characterized approval history for production of clinical grade materials such as recombinant antibody therapeutics.
CHO-S is a known, commercially available (Invitrogen), suspension-adapted CHO cell line. CHO-S is used for expression of recombinant polypeptides in suspension culture and it is considered useful for protein production. However, for increased efficiency of polypeptide production, there is a desire to achieve higher protein expression levels than are achievable using currently available cell lines.
Thus, there is a need to improve the expression of polypeptides in CHO cell lines, to improve efficiency in manufacture of recombinant proteins.
It is an object of the present invention to provide an improved CHO cell line suitable to provide increased polypeptide yields from suspension cultures.